Episcopalians are set to vote Wednesday on allowing religious weddings for same-sex couples, just days after the U.S. Supreme Court legalized gay marriage nationwide.

In 2003, the U.S. branch of the global Anglican Communion made the trailblazing move of electing the first openly gay bishop. Since then, many dioceses have allowed their priests to perform civil same-sex weddings.

Still, the church hadn't changed its own laws on marriage.

The vote on gay marriage is expected around midday in Salt Lake City at the denomination's national assembly.

On the eve of the U.S. vote, Archbishop of Canterbury Justin Welby, spiritual leader of the world's Anglicans, released a statement expressing deep concern about the potential impact of changing the definition of marriage in Episcopal church law.

Ties among Anglicans have been strained since Episcopalians in 2003 elected Bishop Gene Robinson, who lived openly with his male partner, to lead the Diocese of New Hampshire. Welby has been struggling to keep good relations among the churches.

The proposal would eliminate gender-specific language from church laws on marriage so religious weddings can also be performed for same-sex couples. Clergy could decline to perform the ceremonies. Right now, each bishop decides whether his or her priests may conduct gay marriages.

Among mainline Protestant groups, only the United Church of Christ and the Presbyterian Church (U.S.A.) allow same-sex weddings in all their congregations. The Evangelical Lutheran Church in America allows individual congregations to decide on the ceremonies, and the United Methodist Church bars gay marriage.

Robinson, now retired, expressed amazement about how quickly the gay rights movement has progressed since he was getting daily death threats and wore a bulletproof vest to his consecration 12 years ago.

He said all religions will be under more pressure to get in step with society, driven by their own gay and lesbian parishioners who will want to marry within their faiths.

“Conservative churches are hemorrhaging young people because young people today have gay, lesbian, bisexual and transgender friends,” Robinson said.

After the Supreme Court ruling last week, many theologically conservative churches, including the Southern Baptist Convention and the Mormon Church, renewed their opposition to gay marriage.

The Episcopal Church has already made history during the convention, electing its first African-American presiding bishop, Bishop Michael Curry of North Carolina.

Curry supports gay rights, speaking against North Carolina's 2012 constitutional amendment that banned same-sex marriage, which was invalidated by the Supreme Court. In a news conference after his election Saturday, Curry said the Supreme Court “affirmed the authenticity of love” by legalizing gay marriage nationwide.